Artificial lighting based on solid state devices, such as light emitting diodes (LEDs), is used in production of plants as a substitute for natural light or as a supplement to natural light to promote plant growth. LED luminaires are well suited for this purpose as they provide light of the desired wavelength. Also, the LED components do not heat up in the same way as conventional lamps, so they can be placed very close to the plant.
Such luminaires usually have one or more light emitting diodes mounted in an enclosure assembly having a transparent portion covering the LEDs so that the light emitted by LEDs can radiate through the transparent portion towards the plants. However, although designed to be used in production of plants, under humid and wet conditions, such as greenhouses, the enclosure assemblies are often relatively open in such way that their protective capabilities for the underlying electrical parts are not very high or the mechanical solution to reach high humidity protection becomes costly in components and/or to manufacture. In some cases, the tightness of the transparent portions is often even inadequate whereby water and dirt can get inside the luminaires.
Secondly, even if horticultural LED luminaires have long use-lives, reaching up to 40 000 hours, with only small decay, they too experience decay. The light decay is a result of the LED output being lowered over time. In order to continue benefitting of the non-decaying parts, like the aluminum heatsink, cabling and possibly electrical connectors and to benefit from the parts decaying slower than the LEDs, like power units, the user would benefit from the possibility of exchanging the LED portion of the LED luminaire at an cost, lower than acquiring a new LED luminaire with power units etc. This is not currently possible, as there are no suitable technical solutions available.